-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 032300
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
600 PM EST TUE DEC 3 2013

.SYNOPSIS...
MILD CONDITIONS WILL CONTINUE INTO THURSDAY AHEAD OF A STRONG COLD
FRONT WHICH WILL BRING RAIN THURSDAY AND THURSDAY NIGHT. MUCH COLDER
AIR WILL ARRIVE FRIDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
ADJUSTED HOURLY TRENDS TO BETTER CAPTURE THE HIGH TEMPERATURES
FROM TODAY AS WELL AS A VERY RAPID DECLINE IN THE SURFACE
TEMPERATURES THE FIRST FEW HOURS OF THIS EVENING. SATELLITE
IMAGERY REVEALED AN AREA OF NEARLY CLEAR SKIES FROM FRANKLIN TO
WASHINGTON TO MORGANTOWN AND ALL POINTS EAST. IN THIS
AREA...TEMPERATURES HAVE COOLED RAPIDLY THE PAST HOUR. WHILE LOW
TEMPERATURES WERE NOT PARTICULARLY CHANGED OUTSIDE OF THE FAR EAST
AND NORTHEAST...THE TREND TO ALLOW COOLING THIS EVENING THEN
STABILIZATION OF THE DIURNAL TREND WITH THE ADVANCE EASTWARD OF
MID AND HIGH CLOUDS FROM OHIO WAS BETTER DEPICTED IN THE THE GRID.

OTHERWISE...A MAINLY DRY NIGHT STILL LOOKS ON TAP AS A WEAK WAVE
TO OUR WEST LIFTS NORTHEAST OVERNIGHT. AT THE MOMENT...IT IS ONLY
GENERATED ON VIRGA ON RADARS TO OUR WEST/NORTHWEST...AND GIVEN
MOISTURE PROFILES...IT WOULD SEEM UNLIKELY TO GENERATE ANY
PRECIPITATION IN OUR AREA. AS A RESULT...THE DRY FORECAST
CONTINUES FOR TONIGHT. FRIES
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
RAIN CHANCES WILL BE INCREASING INTO THURSDAY AND THURSDAY NIGHT AS
AN ARCTIC FRONT PUSHES EAST TOWARD THE REGION. FRONT WILL BE
SLOWED BY A FLAT WAVE MOVING NORTHEAST ALONG IT THURSDAY WITH A
WIND SHIFT BEHIND. MAIN PUSH OF COLD AIR WILL BE FRIDAY. CAT POPS
THURSDAY NIGHT AND FRIDAY ACROSS THE SOUTH WHERE DEEPEST MOISTURE
AND LIFT WILL REMAIN ENTRENCHED. BY FRIDAY ANOTHER FLAT WAVE WILL
SLOW THE COLDER AIR DOWN AND HELP KEEP PRECIP GOING ACROSS THE
REGION ALL DAY. AS 850MB TEMPS COOL EXPECT A MIX TO SNOW FROM
NORTH TO SOUTH DURING THE DAY. FORECAST SOUNDING ALSO SHOW LOW
LEVEL ARCTIC AIR UNDERCUTTING SLOWER COLD ADVECTION AT 850MB AND
HAVE ADDED A CHANCE FOR SLEET MOST LOCATIONS. BEST QPF AND DEEP
MOISTURE LOOKS TO BE EXITING AS THIS OCCURS SO NO SIGNIFICANT
ACCUMULATIONS. CLOSE TO MODEL MOS THROUGH THE PERIOD WITH
TEMPERATURES FALLING FROM MORNING HIGHS FRIDAY.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
WHILE THE MODELS SEEM TO AGREE ON A SIMILAR UPPER LEVEL
PATTERN...WITH A BUILDING HIGH OVER THE SOUTH ATLANTIC/FLORIDA AND A
DIGGING TROUGH IN THE WESTERN CONUS...THERE CONTINUES TO BE
DIFFERENCES IN THE STRENGTH AND PLACEMENT OF THE NEXT LOW PRESSURE
SYSTEM PROGGED TO DEVELOP OVER THE STALLED FRONTAL BOUNDARY SOUTH
OF THE REGION SUNDAY NIGHT AND MONDAY. THE ECMWF HAS THE
PLACEMENT OF THE SURFACE LOW OVER THE WESTERN GREAT LAKES...WHILE
THE GFS HAS THE LOW DEVELOPING AND CROSSING RIGHT THROUGH THE OHIO
VALLEY. THIS COULD HAVE MAJOR IMPLICATIONS ON PRECIPITATION TYPE
BUT WITH IT BEING ONLY TUESDAY...OPTED TO KEEP THE FORECAST
SIMPLE. MODEL ENSEMBLES KEEP THE LOW FAR ENOUGH WEST AT THIS POINT
TO HAVE A CHANGEOVER TO RAIN FOR MOST OF MONDAY. HAVE BUMPED UP
POPS TO LIKELY FOR SUNDAY NIGHT.

BEYOND MONDAY THE MODEL SOLUTIONS DIVERGE A BIT...SO OPTED TO KEEP
CLOSE TO WPC VALUES. TEMPERATURES CONTINUE TO TREND 5 TO 10 DEGREES
BELOW SEASONAL AVERAGES THROUGH THE PERIOD.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
CLOUDS HAVE FINALLY SCATTERED OUT THIS AFTERNOON...WITH MID LEVEL
CLOUDS EXPECTED TO COVER THE AREA ONCE AGAIN BY SUNSET. WITH LIGHT
WINDS OVERNIGHT AND A LOW LEVEL INVERSION SETTING UP...THINK THAT
MOISTURE LEFT OVER FROM EARLY MORNING RAIN COULD ALLOW FOR SOME
REDUCTION IN VISIBILITIES AGAIN. EXCEPT FOR MGW...WHICH NEVER HAD A
DROP IN VISIBILITY THIS MORNING...AND FKL/DUJ...WHICH SHOULD SEE IFR
CIGS DEVELOP...HAVE GONE WITH MVFR VISIBILITIES OVERNIGHT INTO
WEDNESDAY MORNING. HAVE HELD ONTO RESTRICTIONS INTO MID MORNING
WEDNESDAY SINCE VISIBILITIES WITH BR/FG WERE SLOW TO REBOUND THIS
MORNING.

.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
CHANCE FOR WIDESPREAD RESTRICTIONS COMES WITH THE FRONTAL
BOUNDARY THAT IS EXPECTED TO STALL OVER THE REGION WEDNESDAY
NIGHT. SEVERAL SYSTEMS MOVING ALONG THIS BOUNDARY WILL CONTINUE
RESTRICTION CHANCES THROUGH THE BEGINNING OF THE WEEKEND BEFORE
CONDITIONS DRY OUT SATURDAY. A CHANCE FOR A RAIN/SNOW MIX WILL
RETURN ON SUNDAY.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$